Atrial septal defects are a common congenital heart disease in childhood and are more common in females. Depending on the anatomical lesion, atrial septal defects can be categorized as atrial septal failure, first foramen ovale defects and second foramen ovale defects. The second foramen ovale, also called the secondary foramen ovale, is located in the middle of the atrial septum at the fossa ovalis or near the superior and inferior vena cava and is mostly 1 to 3 centimeters in diameter. Secondary foraminal septal defects have the potential for spontaneous closure if the size of the defect is less than 3 to 5 millimeters.